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Philadelphia SARS-COV-2 antibody study of pregnant women shows five times as many Black or Latino women with antibodies: NYT


Coronavirus studies by Engin Akyurt via

The New York Times (NYT) published an article on July 10 about a study published in MedRxiv on July 8  that showed that a much higher proportion of pregnant women who identified as Black or Hispanic were SARS-COV-2 antibody positive than of women who identified as White.  The study was performed on de-identified blood samples taken from 1,293 pregnant women who presented for delivery at two Philadelphia hospitals between April 4 and June 3.  The hospitals together deliver about 50% of all women in the Philadelphia area.

The results show that there were significant race/ethnicity differences in seroprevalence rates with higher rates in Black/non-Hispanic (9.7%) and Hispanic/Latino (10.4%) women and lower rates in White/non-Hispanic (2.0%) and Asian (0.9%) women.  The number of Asian women in the sample was probably too small to allow conclusions about the significance of their low positivity rates.  Overall, 80/1293 (6.2%) of samples were positive for IgG or IgM antibody (or both.)

In addition, nasopharyngeal swab specimens were obtained from 1,109 (85.8%) women who were also tested for antibodies; however, these were obtained at various times before delivery so they could not be directly compared with the antibody tests.  “We found that 46 of 72 seropositive women (at the time of delivery) who were NP tested had a SARS-CoV-2 positive PCR result (at some point during their pregnancies), whereas only 18 of 1,037 seronegative women (at the time of delivery) who were NP tested had a SARS-CoV-2 positive PCR result” (at some point.)  Thus, the 18 positive PCR tests were in some sense discordant with the antibody tests.

What was striking, however, was the difference in seropositivity between Black or Hispanic women and the White women– about five times as many of the Black or Hispanic women had positive antibody tests.  It seems that there is much greater exposure to the virus among these ethnic groups.

The data should be compared to information in another NYT article published July 5 based on a Freedom of Information Act lawsuit.  The CDC data revealed by the lawsuit provides “detailed characteristics of 640,000 infections detected in nearly 1,000 U.S. counties.”  That data says that three times as many Black or Hispanic people per 10,000 population were infected with the virus as White people and that twice as many died.  “For people who are Asian, the disparities were generally not as large, though they were 1.3 times as likely as their white neighbors to become infected.”

In Missouri, for example, “40 percent of those infected are Black or Latino even though those groups make up just 16 percent of the state’s population.”  Native Americans were far more likely to be infected as well.  Another example:  “In Kent County, which includes Grand Rapids and its suburbs, Black and Latino residents account for 63 percent of infections, though they make up just 20 percent of the county’s population.”

The test results revealed by the CDC are incomplete; of 1.5 million positive antigen tests, only 640,000 had information as to the subject’s ethnicity.

For age-specific test results, the disparities in death rates were even greater:

Latino people between the ages of 40 and 59 have been infected at five times the rate of white people in the same age group, the new C.D.C. data shows. The differences are even more stark when it comes to deaths: Of Latino people who died, more than a quarter were younger than 60. Among white people who died, only 6 percent were that young.

Whether people in these ethnic groups were infected because they were among “essential” workers who were exposed on the job or because they were in households that had greater exposure (or both) is unknown.  Either way, Black or Hispanic people are being infected at about three to five times the rate of White people.  They are also more likely to get sick or die because so many of them have “co-morbid” medical conditions.  Does this have anything to do with the widespread denial of the impact of the virus among Republicans?

It is no wonder that public anger over the murder of George Floyd has become so prevalent in the last two months.  Black people are being struck down by the virus and are being brutalized by the police at the same time.  They have a right to be angry.


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